优于天然美白活性剂熊果苷生理活性的6'-O-咖啡酰熊果苷(CA)以23%的罕见高含量存在于云南省武定县产野生樟叶越桔叶芽中，这为大量生产天然美白活性剂提供了可能。但CA生物合成关键酶基因及其代谢通路仍不清楚，这也限制了樟叶越桔CA的生物学功能研究。课题组前期研究推测CA合成关键酶基因为绿原酸:熊果苷-O-咖啡酰基转移酶基因(VdCAT)，但仍缺乏实验证据。本项目拟在前期工作基础上，采用分子生物学、基因工程和化学生物学等手段，筛选克隆高活性表达的VdCAT候选基因，建立樟叶越桔遗传转化体系，创制VdCAT基因体内干扰和超表达的樟叶越桔材料，分析CA含量变化，明确樟叶越桔CA生物合成的分子基础，阐明CA合成关键酶基因及其产物的生物学功能，为高产CA樟叶越桔的遗传改良及其开发利用提供科学依据。

6’-O-caffeoylarbutin(CA) with rare high content of 23% (dry weight) appeared in the buds of wild Vaccinium dunalianum Wight from Wuding, Yunnan, China and had higher physiological activities than arbutin which widely used in cosmetic formulations as natural active agents to whiten the skin because of control of the formation of melanin. It would be possible that mass production of natural whitening active agent would be achieved. However, the key synthase genes of CA have not been cloned and functionally characterized and the metabolic pathways of CA are still unclear, which limits the research on CA biological function in V. dunalianum. It is speculated that the candidate genes of key synthases chlorogenic acid: arbutin-O-caffeoyltransferase(VdCAT) involved in CA biosynthesis, but with no experimental evidence. Based on previous studies, the project will screen and clone the VdCAT genes with high expression in the buds, establish genetic transformation system and VdCAT RNAi and overexpression vectors, generate transgenic materials, compare the differences in CA content and candidate genes expression in V. dunalianum thorough molecular biology, genetic engineering and chemical biology approaches. The main aims are to clarify the molecular basis of CA biosynthesis and elucidate the biological functions of VdCAT genes and its product enzymes in CA synthesis in V. dunalianum. These results will be beneficial for genetic improvement and development and utilization of CA high-yield plant V. dunalianum.